Censors in China are deleting online mentions, tributes, and references to the death of political prisoner Liu Xiaobo, according to the British newspaper The Times.

Liu was a Nobel laureate and a political dissident who died in the Chinese government's custody on Thursday. He was jailed in 2009 for drafting a petition calling for democracy in China.

He was awarded the Nobel peace prize in 2010 while imprisoned.

The Chinese government is concerned that Liu will now become a greater symbol of the hope for democracy in China than he was during his life, according to The Times.

Hundreds of thousands attempted to post tributes to Liu, but censors quickly purged mentions of his name, drawings of him, and photographs of candles, which are posted as remembrances of deceased people, The Times reports.

On Weibo, China's version of Twitter, emojis of candles were also deleted and one user posted the message "RIP," and was told that the message "violated relevant laws and regulations," the newspaper said.

Some online posters attempted to bypass the censors by posting images of text tributes to Liu, because images are more difficult to scan for phrases that are banned. Other tributes referenced Liu indirectly, The Times reports.

Chinese media reported little about Liu's death from cancer and China's leadership in Beijing refused to allow the U.S. to take Liu for treatment, The Times reports.

"The Chinese government bears a heavy responsibility for his premature death," said Berit Reiss-Andersen, the chairman of the Norwegian Nobel committee, according to The Times.

U.S. Secretary of State Rex Tillerson issued a statement on Thursday calling on Beijing to release Liu's wife, Liu Xia, from house arrest and allow her to leave China.

"In the fight for freedom, equality, and constitutional rule in China, Liu Xiaobo embodied the human spirit that the Nobel Prize awards. In his death, he has only reaffirmed the Nobel Committee's selection," Tillerson said.